Study on Growth of Oxide Scale on High Carbon Steel at High Temperature

Abstract

Abstract：To control the oxide scale on high carbon steel during the manufacture of high carbon steel wire, the structure and the growth process of oxide scale were investigated by using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) , Laser Raman Spectroscopy (LRS) and TGA system. Experimental results show that oxide scale on high carbon steel has a three-layer structure. The oxide scale growth on high-carbon steel can divide into three stages. 1) The growth rate is slow below 780°C. 2) The growth rate increases obviously between 780°C and 950°C and 3) sharp increase beyond 1000°C. The oxidation of high carbon steel obeys a linear law at first and a parabolic law is followed with the increase of oxidation time. The oxide temperature has great effected on the thickness of oxide scale. The proportion of wustite in oxide scale increases with both the oxidation temperature and oxidation time.

Kinetic Study of Oxide Growth at High Temperature in Low Carbon Steel

“…The surface oxidation of steel is complex because it depends on many factors such as oxidation time, temperature, alloying elements, and oxidizing atmosphere [10]. It should be clarified that the removal of the oxide layer between stages with high-pressure water could generate imperfections on the surface of the rolled steel, causing cracking problems [11,12]. In general, the oxidation of steel at high temperature is similar to that of pure iron Fe composed by the sequence of oxide layers growth (FeO/Fe 3 O 4 /Fe 2 O 3 /O 2 ): (1) wustite (FeO), a thick inner layer formed by ionic reaction between metallic iron Fe and oxygen in the atmosphere, (2) magnetite (Fe 3 O 4 ) [13], a thin intermediate layer formed by the reaction between wustite and oxygen ions whose growth is based on the formation of the outer layer, and (3) hematite (Fe 2 O 3 ), which is a thin layer that is characterized by containing the highest amount of oxygen and serving as the supply of Fe cations for the formation of magnetite [9]; that is, a cooperative growth occurs, where the cations for the growth of hematite come from the magnetic one, while the anions come from the hematite, which has been corroborated by theoretical calculations by Schwenk and Rahmelt [13].…”